Computer Architecture - Hardware - Lesson 7 - Hard Drive - Eric Vanderburg

1. Computer Architecture:
Core Hardware
Chapter 7
Hard Drives
Eric Vanderburg
Eric Vanderburg – Core Hardware © 2005

2. Interfaces
• ATA Standards – pg. 245
• ATA is Parallel PATA (Parallel ATA)
• SATA (Serial ATA)
• UltraATA cable has 80 wires instead
of 40.
• Autodetection
Eric Vanderburg – Core Hardware © 2005

3. Components
• Platter – glass/ceramic with magnetic
coating
• Logic Board
• Heads – spring loaded and forced to
connect with the platter. Spinning keeps
them above.
• Sliders – Pieces on either side of the head
to protect it.
• Connectors
• Actuator – shaft that allows pivoting
• Spindle Motor – moves the head pieces
back and forth.
• Jumpers
Eric Vanderburg – Core Hardware © 2005

4. How it works
• Head rides on cushion of air
– (ex: plane 2 feet off the ground at
500Mph)
– 5 millionths of an inch from the platter
• Head on either side of platter (round
disk)
• Head crash – head touches down
while spinning
• Landing Zone – Where the heads
park when the drive powers down.
Eric Vanderburg – Core Hardware © 2005

5. • Areal Density – BPI (Bits Per Inch)
multiplied by TPI (Tracks Per Inch) =
MB/GB per square inch.
• As AD increases, the head must ride
closer to the platter. This requires
more precision.
• From 3,600RPM to 10,000RPM
• Nonvolatile data storage – does not
change when power is removed.
Eric Vanderburg – Core Hardware © 2005

6. Partitions & Formats
• Low Level Formats – Maps the
original tracks and sectors
• Partitioning
• Formatting – OS defines sections of
the drive for use
Eric Vanderburg – Core Hardware © 2005

7. SMART
• SMART (Self Monitoring Analysis and
Reporting Technology) – Monitors
drive status to predict when it will
fail. Monitors:
– Head Floating Height
– Data Throughput Performance
– Spin-up Time
– Seek error rate
Eric Vanderburg – Core Hardware © 2005

8. Caching & Skew
• SMARTDRV & Vcache – cache data
from the drive for increased speed.
Eric Vanderburg – Core Hardware © 2005
• Head skew
• Cylinder Skew

9. Eric Vanderburg – Core Hardware © 2005
Formats
• FAT16
• FAT32
• NTFS

10. Eric Vanderburg – Core Hardware © 2005
Formats
• FAT16
• FAT32
• NTFS